US M&A deals of the month: August 2026

The largest US-linked deals announced in August clustered around businesses that control how customers, capital, data, medicines, and energy move. Insurance distribution, AI model routing, radiopharmaceutical infrastructure, investment management, and natural gas networks all drew multibillion-dollar commitments, extending a year in which buyers have repeatedly favoured established platforms over slower organic expansion.

Deal activity remained strong enough to support that confidence. EY-Parthenon’s latest US M&A analysis, covering transactions worth at least $100m between May and July, recorded a 58% year-on-year increase in deal value and a 21% increase in volume. Technology deal value rose 161%, power and utilities increased 329%, and life sciences advanced 71%, reflecting the concentration of capital in sectors already absorbing heavy investment.

That momentum carried into August, although valuation discipline remained visible. Several of the month’s largest transactions were built around businesses with existing customer relationships, regulatory approvals, physical infrastructure, or specialist technology that would take years to reproduce, while financing structures placed clear demands on future earnings, leverage, and capital allocation.

July’s US M&A review had already shown capital concentrating around distribution networks, advanced materials, energy infrastructure, market plumbing, and logistics property. August pushed further into assets that sit at important control points within their markets, from insurance brokerage and AI routing to investment distribution and gas transmission.

Five transactions captured that pattern.

Aon makes a $17bn middle-market bet —

Aon ended August with the month’s largest newly announced transaction among the leading US-linked deals, agreeing to acquire USI Insurance Services from KKR and other shareholders for $17bn.

USI is the tenth-largest US insurance broker, generating approximately $3bn of annual revenue and employing more than 10,500 people across nearly 200 offices. Its business spans property and casualty insurance, employee benefits, personal risk, retirement services, and the excess and surplus market, giving Aon a much broader position across the US middle market.

Following its acquisition of NFP in 2024, Aon is again using M&A to expand a distribution model in which client relationships, proprietary data, specialist advice, and technology can reinforce one another. USI also brings its USI ONE analytics and planning platform, allowing Aon to add national reach and established commercial infrastructure without building comparable coverage office by office.

The purchase price places substantial weight on delivery after completion. Aon puts the net consideration at $16.7bn after certain tax attributes, equivalent to approximately 14.5 times synergised trailing adjusted EBITDA, and expects around $395m of annual run-rate net adjusted EBITDA benefit from revenue and cost synergies. Adjusted earnings per share are expected to benefit from 2028.

Debt will do much of the financing work. Aon plans to issue new borrowing across a range of maturities, prioritise deleveraging after completion, and suspend near-term share repurchases, so the acquisition will shape capital allocation well beyond the closing date. Subject to regulatory approvals and other conditions, completion is expected in the fourth quarter of 2026.

Stripe buys deeper into AI infrastructure —

Stripe agreed to acquire OpenRouter on 19 August, adding a platform that sits between AI users and more than 400 models supplied by over 80 providers. Financial terms were not disclosed by the companies.

OpenRouter allows developers and businesses to access multiple models through a single interface and route workloads according to variables including task complexity, price, speed, and reliability. As companies use a wider mix of AI systems, that routing function can influence both operating cost and application performance.

Stripe already manages a comparable layer in payments, where its infrastructure connects businesses with multiple payment methods, currencies, fraud controls, authorisation systems, and markets. Its expansion into token billing and other AI-related services has moved it closer to the economics of machine-generated usage, while OpenRouter extends that position into the allocation of workloads themselves.

Companies deploying AI at scale are increasingly selecting models according to the requirements of individual workloads rather than making a single technology choice. Different applications can justify different combinations of cost, latency, accuracy, and resilience, while model availability and pricing can change quickly. Software capable of routing those workloads can therefore affect both the economics and reliability of enterprise AI deployments.

OpenRouter gives Stripe a position between enterprise demand and a fragmented model market, extending its exposure to how AI consumption is directed, measured, and ultimately paid for.

Curium pays up for radiopharma reach —

Curium agreed to acquire Massachusetts-based Lantheus in a transaction worth up to approximately $8bn, combining substantial positions in radiopharmaceutical diagnostics and therapeutics.

Lantheus shareholders are due to receive $102.50 per share in cash at closing, together with contingent value rights worth up to another $12 per share if specified commercial milestones are achieved through 2030. Maximum consideration of $114.50 per share represents a 38% premium to Lantheus’s unaffected 60-day volume-weighted average price.

The contingent element gives the buyer and seller a way to share future product risk rather than forcing the entire valuation into the upfront price. In healthcare markets shaped by clinical pipelines, regulatory milestones, and uneven commercial adoption, that structure can keep a transaction viable even when the eventual value of developing products remains uncertain.

Curium contributes isotope production, manufacturing, and a developing radioligand therapy portfolio, while Lantheus brings US commercial infrastructure and established diagnostic franchises across prostate cancer imaging, cardiac ultrasound, and neurological imaging. Together, the companies would operate across diagnostics and targeted radioligand therapy, serving patients in more than 70 countries.

Replicating that breadth independently would require manufacturing capacity, isotope supply, regulatory approvals, clinical development, specialist commercial teams, and long-standing relationships with healthcare providers. The acquisition compresses that development cycle, although the final economics will still depend partly on the commercial milestones embedded in the contingent consideration.

Completion is expected during the first half of 2027, subject to Lantheus shareholder approval and regulatory clearances.

Victory Capital buys towards $1tn scale —

Victory Capital agreed to acquire First Eagle Investments for approximately $7bn, adding another large financial-services transaction to a month already dominated by Aon’s move for USI.

First Eagle managed approximately $222bn at the end of July across multi-asset, equity, fixed-income, collateralised loan obligation, and alternative-credit strategies. Combined with Victory Capital, the enlarged group is expected to oversee approximately $571bn in total client assets.

The acquisition expands both scale and product breadth. First Eagle contributes a $41bn CLO and alternative-credit operation, giving Victory a larger position in private and structured credit, while its wider product range brings investment strategies that recorded positive net flows over the previous three years. Victory intends to retain First Eagle’s brand, investment autonomy, and investment processes while placing the business on its broader operating and distribution platform.

Approximately $4.4bn of the consideration will be paid in cash and $2bn through newly issued Victory Capital equity, while the buyer will also assume $575m of First Eagle senior secured notes. Victory expects around $280m of net expense synergies and has projected approximately 35% accretion to adjusted earnings per share in 2027.

The financing package includes a new $3.5bn term loan facility and approximately $950m of new secured notes. Completion is expected by the end of the first quarter of 2027, subject to regulatory approvals, client consents, and shareholder approval for the equity issuance.

Much of the value will depend on whether Victory can centralise technology, administration, distribution, and corporate functions without disturbing the investment teams and client relationships that support First Eagle’s revenues. Asset management offers meaningful economies of scale, but client retention and investment performance remain closely tied to people and process.

Williams secures another route to energy demand —

Williams agreed to acquire Momentum Midstream for consideration of up to $5.5bn, deepening its position in the Haynesville shale as Gulf Coast LNG facilities, industrial users, and power generators compete for growing gas supply.

The package comprises approximately $3.5bn of cash and debt consideration and around $2bn of Williams equity. Momentum brings more than 4,000 miles of pipeline, over one million dedicated acres, gathering capacity of 6bn cubic feet per day, and three take-or-pay pipelines capable of moving approximately 4.05bn cubic feet per day.

Rising power demand is strengthening the economics of infrastructure that connects gas production with large centres of consumption. Data-centre construction is adding another source of load alongside LNG exports and industrial demand, increasing the value of networks that already sit between producing basins and customers with long-term requirements.

Williams operates infrastructure linking major gas-producing regions with demand centres across the US. Momentum expands its gathering and transportation position in the Haynesville basin and provides a platform for further capital deployment, including the planned $1.5bn Delta Access project, which is expected to provide initial capacity of 2.25bn cubic feet per day from the first quarter of 2029.

The acquisition is valued at approximately 8.5 times projected 2027 EBITDA and is expected to increase earnings and available funds from operations per share. Fixed-fee arrangements and take-or-pay contracts give Williams greater visibility over cash generation as it commits further capital to expansion.

Bottom line —

August’s largest deals combined aggressive capital deployment with comparatively narrow strategic objectives. Rather than using M&A to move into unrelated markets, buyers generally expanded positions they already understood, acquiring distribution, infrastructure, customer access, specialist capability, or product breadth that could be integrated into existing platforms.

Aon and Victory Capital provide two clear versions of that approach. Aon is paying $17bn for a national insurance distribution network, established middle-market relationships, data, and technology, while Victory is using First Eagle to increase assets under management, broaden alternative-credit capabilities, and spread operating infrastructure across a larger revenue base. In both cases, scale is tied to specific economics rather than size alone.

Technology investment is also spreading beyond software developers and model creators. Stripe’s OpenRouter acquisition places it inside the infrastructure used to allocate AI workloads, while Williams is investing further down the physical supply chain in gas networks serving growing power demand. Continued spending on data centres, grids, generation, and semiconductors is connecting the AI investment cycle with sectors that supply the computing economy as well as those developing its applications.

Curium’s Lantheus acquisition reflects a similar preference for established capability. Manufacturing, isotope supply, regulatory permissions, clinical development, and commercial reach create barriers that cannot be removed quickly with capital alone. The contingent value rights in the transaction also provide a practical mechanism for sharing uncertainty over future product performance without delaying the combination.

Financing terms place measurable obligations on management after closing. Aon is taking on new debt and temporarily stepping back from share repurchases; Victory is combining cash, new equity, assumed debt, and fresh borrowing; Williams is funding its acquisition with both cash and shares. Each structure affects leverage, future distributions, and the speed at which the acquired business must begin contributing to returns.

Private equity remained active as both seller and buyer. KKR is among the shareholders exiting USI, while earlier in August it agreed a separate $5.7bn acquisition of medical-device manufacturer Integer. Large sponsors with mature portfolios and substantial undeployed capital can recycle proceeds from established holdings into new transactions even while exits across the wider market remain uneven.

Shareholder discipline also interrupted the broader run of large deals. Solstice Advanced Materials and Element Solutions terminated their $14.5bn merger agreement on 27 August following discussions with shareholders, with neither side paying a termination fee. Solstice simultaneously authorised a $500m share repurchase programme.

The reversal was particularly notable because the proposed Solstice transaction had featured prominently in July’s US deal activity. Its collapse showed how quickly the capital-allocation comparison can change once shareholders weigh an acquisition against standalone investment, debt capacity, and direct returns of capital.

Across the stronger August transactions, buyers attached large purchase prices to explicit commitments on earnings accretion, leverage, synergies, contingent payments, or subsequent investment. Capital remains available, but large acquisitions still have to compete with organic growth, buybacks, and debt reduction for the same balance-sheet capacity.

US M&A remains concentrated around assets that give buyers something difficult to recreate quickly: relationships, infrastructure, specialist technology, regulated capability, or market access. The quality of those assets can support substantial premiums, but the financial case ultimately rests on whether management can preserve what was acquired while delivering the returns embedded in the purchase price.

August’s deal flow reflected a market with both capital and conviction, but neither was evenly distributed. Buyers concentrated spending on businesses that already controlled customers, infrastructure, data, specialist capability, or distribution, while transactions with a weaker capital-allocation case remained vulnerable to challenge.

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BQ